generic

   type element is private;

package ppila is
	type bloc is limited private;
	type pila is access bloc;
	subtype pbloc is pila;

	procedure pbuida(p: out pila);
	procedure empila(p:in out pila; e:in element);
	procedure desempila(p:in out pila);   
	function cim(p:in pila) return element;
	function esbuida(p:in pila) return boolean;

	desb_sup:exception;
	desb_inf:exception;
private
   type Bloc is record
      e: element;
      s: pbloc;
   end record;
end ppila;



